TECHNIQUE AND EQUIPMENT FOR EXPRESS FORECASTING OF MATERIALS 
FATIGUE CHARACTERISTICS  
 
S.E. Belski, Candidate of Technical Sciences, Assistant Professor, Head of Department of Machine 
Elements, Hoisting and Conveying Equipment 
Belarusian State Technological University 
 
Design of high-reliability structures operating under vibration involves both the 
development of new construction materials and more precise fatigue characteristics to be used in 
strength calculations. 
Low-frequency fatigue tests involve considerable material costs. To reduce the labour 
intensity of tests under high cycling (108-1010) it is very promising to apply high (sonic and 
ultrasonic) frequencies of cycling which permit the operating time of a set number of load cycles 
and define the mechanisms of the effect which deformation frequency has on the materials fatigue 
life. 
With different cyclic strength values obtained under various frequencies, the relationships 
have been determined between fatigue life parameters and a number of structure-sensitive 
properties of materials. These relationships are based on an integrated research of kinetics of 
physical-mechanical characteristics under alternate stress of a broad amplitude-frequency range.  
A unified physical character of fatigue under high and low frequencies has been proved 
including the fatigue under complex stress. This has formed a basis for the development of a 
physical model demonstrating the impact of vibration frequency on critical stresses at the initial 
stage of fatigue development. This model permitted to scientifically prove the technique of express 
fatigue tests. 
Experimental testing of the technique for express forecasting of low-frequency fatigue was 
based on the results of high-frequency tests of an extended construction materials range. The testing 
revealed the possibility to multiply reduce duration, labour and energy intensity of determining 
fatigue characteristics without any inaccuracy of forecast. 
Landmark instrumentation-equipped testing complexes have been designed and protected by 
inventor’s certificates. These complexes make it possible to generate intensive bending, 
longitudinal and torsional symmetric- and asymmetric-cycle vibrations with a high frequency range 
(0.15-44.0 kHz) as well as to automatically maintain astable operating mode aided by electronic 
devices and allowing fatigue tests to be carried out under constant cyclic stresses. 
A wide range of metal construction materials have been experimentally tested under various 
frequencies and mechanical vibrations of both symmetric and asymmetric cycles under an extended 
temperature range.